On the Cover

The cover shows an atomic force microscope image of the S-layer lattice of SbsB, the S-layer protein of Bacillus stearothermophilus PV72/p2. The image shows the inner, usually cell-bound side of the SbsB S-layer assembled onto a silicon surface. Yellow to green elements indicate the S-layer lattice, black indicates depressions, interpreted as spores in the lattice. The image size is 50x50 nm. The article by Howorka et al., pages 37876-37886 37876, reports on the identification of surface-accessible residues of monomeric and assembled SbsB by using cysteine scanning mutagenesis in combination with targeted chemical modification. Image courtesy of Dietmar Pum and Erika Gyorvary, Center for Ultrastructure Research, University for Agriculture, Vienna, Austria and Stefan Howorka, Department of Medical Biochemistry and Genetics, The Texas A&M University System Health Science Center, College Station, TX. .